Oil-burning-control system



Sept. 10, 1929. A O 1,727,735

OIL BURN ING CONTROL SYSTEM Filed March 12, 1928 g'wuentoz Daniel G.Taylor,

Patented Sept. 10, 19 29.

DANIEL G. TAYLOR, OF MINNEAPOLIS, MINNESOTA, ASSIGNOB TO MINNEAPOLIS HONEYWELL REGULATOR COMPANY, TION OF DELAWARE.

OF MINNEAPOLIS, MINNESOTA, A CORPORA- ODL-BUBNING-CONTBOL SYSTEM.

Application filed March 12, 1928. Serial No. 260,910.

The object of my invention is to provide a control system for oil burners of such.

character that upon an automatic call for heat a delivery of fuel, and ignition means therefor will be initiated, the fuel delivering means comprising an electric motor and an electrically actuated valve in the fuel delivery line; initial fuel delivery will be maintained throughout the heatcalling period provided initial ignition is accomplished and combustion is maintained; fuel delivery will be discontinued upon cessation of demand for heat or upon cessation of combustion, or, within a predetermined time, in case of failure of initial ignition fuel; the fuel igniting means will be automatically discontinued at the end of the predetermined time; and initiation of fuel delivery may not be accomplished unless the apparatus is at a predetermined low temperature and the temperature affecting element withinimmediate influence of fuel combustion 1s in proper operative condition.

It is common practice at the present time to deliver fuel oil to a suitable burner, properly arranged in conjunction with a combustion chamber and heating element such as a furnace or boiler, by means of an electric motor, said motor being commonly called the fuel motor and forcibly delivering either'the oil or the necessary air or both to the fuel nozzle. It is also common practice in apparatus of the kind under consideration to control the flow of. oil by means of a valve the controlling element of which is biased to closed position by a spring and moved to open position by an electric motor of the type capable of being stalled without injury in order to hold the valve in open position for substantial pe-r riods of time. It is also common practice in apparatus of this kind to, utilize mercury switches and warp switches comprising bimetallic blades and means for electrically heating the same. It is also com mon practice to utilize a thermostat con- I trolled circuit controller arranged within the immediate influence of the heat of the combustion chamber and this element, in my construction, I shall for convenience in the system is within the outlet stack of the combustion chamber although it may be arranged at any one of a number of other convenient positions.

The precise details of the various ele-' ments mentioned above, and which are utilized in my controlling device form no part of my present inventionand consequently I have illustrated my invention diagrammatically, the drawing being a diagrammatic illustration ofthe various; elements and their electrical and mechanical relations and connections.

'Referring'to the diagram indicates a power wire connected by wire. 11 with terminal 12 of the room thermostat R. The associated terminal 13 of room thermostat 'R is connected by wire 14 with a fixed terminal 15 contacted by a movable blade 16 biased away from such contact by a spring 17 and held in said contact by the movable element 18 of the safety-warp switch W. Blade 16 is connected by wire 19 witha contact 20 carried by the bimetallic element 21 of the ignition warp switch 'w said contact 20 being normally in contact with the terminal 22 connected by wire 23 with terminal 2-1 of the stack thermostat S said thermostat comprising a terminal companion to terminal 24 at the cold side of the stack thermostat. Terminal 25 is electrically integral with a terminal 25 at the hotend of the stack thermostat and these two terminals (they may be a singleterminal in certain constructions) are connected by a wire 26 with one end of the heatin wire 30 to ground (or to the power line companion to line 10). a e hot end of the stack thermostat S also comprises a terminal 32 companion to the terminal 25' and connected by wire 33 with wire 28. a

Y The motor comprises a rotor 35 connected by a suitable train of gears 36 with ranged in the fuel conduit leading from.

a suitable source'of supply either directly to the fuel nozzle or to a pump controlled by 69, 70 to ground.

the fuel motor. 1

The valve stem 37 is biased to cold position by a spring 41 and the motor VM is of a type which will permit stalling and electrical maintenance installed position with-.

out harm.

The energizing circuit of the fuel motor F comprises a wire connected to ground and a wire 51 connected to a fixed terminal 52 arranged to be contacted by a swinging,

terminal 53 under the control of valve stem 37 as indicated at 52, the contact 53 being biased normally open. Contact 53 is connected by a wire 55 with wire 19 and wire 55 is also connected to a swinging contact 56 normally biased to open position and under the control of valve stem 37 as indicated at 57. Contact 56 coacts witha fixed terminal 58 connected by wire 59 with wire 26.

Terminal 52 is connected by wire 60 with a terminal 61 in the mercury switch 62 which is carried by a tilting carrier 63 which is biased to circuit opening position, most conveniently by over-balanced weight, and is normally heldin circuit closing positionby a pin 64 carried by a valve stem 37 and having a one way engagement with an extension 65 of carrier 63, The termi- V nal 66 of tube 62 is companion to terminal 61 and is'connected by a wire'67 and branch wires 67 and 67 respectively with the heat ing coil 68, of warp switch to, and the pri-- mary ofthe electrical ignition means I.

Coil 68 and the primary ignition means are also connected by wire 69 and this wire is connected by wire 70 to ground.

The blade 21 of the warp switch to is so spaced that, when cold and contact 20'is in contact with terminal 22, the tube carrier 63 will be supported in circuit closing position, against its bias, by blade 21 even though said carrier be released by withdrawal of pin 63.

The diagram shows the parts in what may be termed the normal positions, i. e., a condition of no fuel delivery and no call for fuel delivery.

Upon the call for heat; the room thermostat will swingto circuit closingposition thus closing the circuit 10, 11, 12, 13, 14, 15, 16,19, 20,22, 23, 24, 25, 26, 27,28, 29, 30 to ground thereby energizing the fuel valve motor VM and raising and temporarily maintaining valve 38 from its seat. The

upward movement of valve stem'37 will release tube carrier 63 so that it is then only supported by blade 21, and will also bring contacts 53 and 56 into contact with terminals 52 and 58 respectively thereby closing the fuel motor circuit 11, 12, 13, 14, 15, 16, 19, 55, 53, 52, 51, 50 to ground; and also closing the ignition circuit 11, 12,13, 14, 15, 16, 19, 55, 5s, 52, 60, 61, 66, 67, 67 through 68, and 67 through the ignition primary,

The flow of current through coil 27 will heat blade 18 of warp switch TV and, if maintained a suflicient length of time, will release blade 16 and thus break all circuits at 15 and stop further operation of the apparatus until the device is re-set by hand; the fuel motor stopping delivery of fuel and the fuel valve motor element 38 moving to fuel blocking position under the action of spring 41 and withdrawing contacts 53 and 56 from contact with the nals 52 and 58.

Flow of current through the heating coil 68 for a predetermined time, which will be the time estimated to insure proper ignition of the fuel under normal conditions, will cause a warping-of blade 21 so as to release tube carrier 63 and thus break the ignition circuit at 61-66 so that there will be no loss of current due to necessity of maintaining current in the heating coil of the warp switch 20 after a fuel has been properly ignited.

If combustion is properly initiated the stack thermostat S will bethermally actuated to cause, within a predetermined time,

respective termia break of the fuel valve motor circuit at cuits at 12-13, stop the fuel delivery motor.

and releasing the fuel valve motor so that spring 41'will serve to return element 38 to fuel blocking position and permitting 53 and 56 to move away from their associated terminals, and returning tube 62 to circuit closing position, blade 21 snapping under carrier 62. w

It will be noted that any failure of circuit closing function of the room thermostat, for any reason, renders the apparatus incapable of delivering fuel; that any fail ure of circuit closing function of the stack thermostat at terminals 2425 will render the apparatus incapable of delivering fuel" because the fuel valve motor, will not be actuated and flow of fuel will be blocked at 38; that any failure. of circuit making capacity of the stack thermostat at 2532 will result in discontinuance of fuel delivery because'no maintaining circuit for the fuel valve motor will be produced andthe preceding break at 2425 will release stem-37 and permit spring 41 to drive the element 38 to fuel blocking position and at the same time break the fuel motor circuit at 52-53. If, for any reason, the stack thermostat should become stuck so as to fail to re-' spond freely to temperature variations undesirable fuel delivery would be prevented within a safe time because, if the stack thermostat fails to respond to increased temperature the circuit at 2-1-25 will be maintained and there will be a consequent suflicient flow through coil 27 to actuate warp switch W; and if the stack thermostat sticks in the hot position the fuel delive will be discontinued, as already describe di when the room thermostat moves to heated position and, when it returns to cold or heat-demand position the fuelvalve motor will not be actuated because the initiating circuit is only through terminals 24-25.

For the sake of brevity in the claims the following terms will be used Fuel motor designates an electric motor which actuates means for posit-ively delivering fluid fuel, as for instance oil and air,

, either or both, to a suitable burner; fuel valve designates a movable fuel flow controlling element; a valve motor an electrically energizedelement capable of acting upon the fuel valveto move to and hold it in position against the action of a normal bias acting upon the fuel valve to move the fuel valve to closed position; combustion control a thermostat, or equivalent element comprising an element sensitive ,to combusv tion conditions in or reasonably closely adjacent the combustion chamber of the furnace to be controlled and also comprisingv a circuit-controlling element moved into and out of circuit-making position by reason of the response of the thermostatic element to combustion conditions. The thermostatic element of this structuremight be an element not strictly a thermostat but responsive to variations in intensity of light due to combustion conditions or responsive to variations in temperature due to combustion conditions: timed switch an electric circuit controlling element (most con- *veniently what is known as a. warp switch) capable of maintaining or breaking an electric circuit and responsive at the end of a predetermined time interval to electrical conditions established in an element thereof to modify the circuit controlled by the switch.

I claim as my invention: '1. A controller for fluid fuel burners comprising; a fuel valve biased to closed posithe absence of combustion tion; a valve motor connected to said fuel valve to open the same; a combustion control comprising two oppositely set circuit breakers, 0118 in circuit-making position in and one in circuit-making position in the presence of combustion; an energizing circuit for the valve motor comprising in series a starting switch, a timed switch normally biased ,to open position, an automatically resetting timed switch,the cold-closed circuit breaker of the combustion control and the electrical timed element of the first-mentioned timed switch; a shunt circuit for shunting the .electrical timed element of the first-mentioned timed switch, said shunt being connected to the energizing circuit of the valve motor and comprising a switch biased-o en and closed by opening movement of the uel valve and also comprising the hot-closed circuit breaker of the combustion control.

2. A controller for fluid fuel burners comprising, a fuel valve biased to closed position; a valve motor connected to said fuel valve to open the same; a combustion controlcomprising two oppositely set circuit breakers, one in'circuit-making position in theabsence of combustion and one in circuit-making position in the presence of combustion; an energizing circuit for the valvemotor comprising in series a starting switch, a timed switch normally biased to open position and non-automatlc in reset-' ting, an automatically resetting timed switch, the cold-closed circuit breaker of the combustion control and the electrical timed elementof the first-mentioned timed switch; a shunt circuit for shunting the electrical timed element of the first-mentioned timed switch, said shunt being connected to the energizing circuit of the valve motor and comprising a switch biased-open and closed 7 by opening movement of the fuel valve and also comprising the hot-closed circuit breaker of the combustion control.

3. A controller for fluid fuel burners comprising a fuel valve biased to closed position; a valve motor connected to said fuel valve to open the same; a combustion control comprising two oppositely set circuit breakers, one in circuit-making position in the absence of combustion and one in circuitmaking position in the presence of combustion; an energizing circuit for the valve motor comprising in series a starting switch,

a timed switch normally biased to open position and non-automatic in resetting, an automatically resetting timed switch, the coldclosed circuit breaker of the combustion control and the electrical timed element of the fi'rst-mentioned-timed switch; a shunt circuit for shunting the electrical timed element of; the first-mentioned timed switch,

said shunt being connected to the energizing circuit of the valve motor and comprising a switch biased-open and closed by opemng movement of the fuel valve and also comprising the hot-close d circuit breaker of the combustion control; a fuel motor; an energizing circuit for the fuel motor comprising the starting switch, the first-mentioned timed switch and a biased-open switch closed by movement of the fuel valve to open position.

.4. A controller for fluid fuel burners comprising a fuel valve biased to closed position; a valvemotor connected to said fuel valve to open the same; a combustion control comprising two oppositely set circuit breakers,

one in circuit-making position in the absence valve motor and comprising a switch biased open and closed by opening movement of the fuel valve. and also comprisingthe hotclosed circuit breaker of the combustioncontrol; a fuel motor; an energizing circuit for the fuel motor comprising the starting switch, the first-mentioned timed switch and a biased-open switch closed by movement of the fuel valve to open'position; electric ignition means; and an energizing circuit for said electrical ignition means, comprising a timed electrical element aifecting the secondmentioned timed switch.

' 5. A controller for fluid fuel burners comprising a fuel valve biased to closed position; i

a valve motor connected to said-fuel valve to open the same; a combustion control comprising two oppositely set circuit breakers, one in circuit-making position in the absence of combustion and one in circuit-making position in the presence of combustion; an en- '-ergizing circuit for the valve motor comprising in series a starting switch, a timed switch normally biasedito open position and non-automatic in resetting, an automatically resetting timed switch, the cold-closed circuit breaker oft-he combustion control and the electrical timed element of the first-menioned timed switch; a shunt circuit for shunting the electrical timed element of the first-mentioned timed switch, said shunt bemg connected to the energizing circuit of the valve motor and comprising a switch biasedopen and closed by opening movement of the fuel valve and also comprising the hot-closed circuit breaker of the combustion control; a fuel motor, an energizing circuit for the fuel motor comprising the starting switch,

the first m'ent'ioned timed switch and a biased-open switch closed by moi ement of the fuel valve to open position; electric ignition means; and an energizing circuit for said electr cal ignition means com rising a timed electrical element afi'ecting t e second-men:

tioned timed switch and also comprising a circuit breaker biased to open position, a movable element of the second timed switch being arranged to hold said last-mentioned circuit breaker against its bias; and means actuated by the fuel valve, in its closing movement, to move said last-mentioned circuit breaker against its bias tocircuit-closing position.

6. A controller for fluid fuel burners comprising, a fuel valve biased to closed position; a valve motor connected to said fuel valve to open the same; a combustion control comprising two oppositely set circuit breakers, one in circuit-making position in the absence of combustion and one. in circuitmaking position in the presence of combustion;an energizing circuit for the valve motor comprising in series a starting switch, a timed switch normally biased to open position, an automatically resetting timed switch, the cold-closed circuit breaker of the combustion control and the electrical timed element of the first-mentioned timed switch; a shunt circuit for shunting the electrical timed element-of the first-mentioned timed switch, said shunt being connected to the energizing circuit of the valve motor and comprising a switch biased-open and closed by opening movement of the fuel valve and also comprising the hot-closed circuit breaker of the combustion control; a fuel motor; an energizing circuit" for the fuel motor comprising the starting switch, the' first-mentioned timed switch and a biased-open switch closed by movement of the fuel valve to open position. 7. A controller for fluid fuel burners comprising a fuel valve biased to closed position; a valve motor connected to said fuel valve to open the same; a combustion control comprisingtwo oppositely set circuit breakers, one in circuit-making position in the absence of combustion and one in circuitmaking position in the presence of combustion; an energizing circuit fonthe valve motor comprising in series a starting switch, a timed switch normally biased to open position,'an automatically resetting timed switch,

the cold-closed circuit breaker of the combusa tion control and the electrical timed element of the first-mentioned timed switch; a shunt circuit for shunting the electrical timed eleinent of the first-mentioned timed switch, said shunt being connected to the energizing circuit of the valve motor andjcomprising a switch biased-open and closedby openingmovement of the fuel valve and also comprising the hot-closed circuit breaker of the combustion control; a fuel motor; an energizing circuit for the fuel motorcomprisin the starting switch, the first-mentioned tlmed switch and a biased-open switch closed by movement of the fuel valve to open position; electric ignition means; andan energizing circuit for said electrical ignition means,

comprising a timed electrical element afiect-. ing the second-mentioned timed switch.

8. A controller for fluid fuel-burners comprising, a fuel valve biased to closed position; a valve motor connected to said fuel valve to open the same; acombustion control comprising two oppositely set circuit breakers, one in circuit-making position in the absence of combustion and one in circuitmaking position in the presence of combustion an energizing circuit for the valve motor comprising in series a starting switch, a timed switch normally biased to open position and non-automatic in resetting, an automatically resetting timed switch, the coldclosed circuit breaker of the combustion control and the electrical timed element of v the first-mentioned timed switch; a shunt circuit for shunting the electrical timed element of the first-mentioned timed switch,

said shunt being connected to the energizing circuit of the valve motor and comprising a switch biased-open and closed by opening movement of the fuel valve and also comprising the hot-closed circuit breaker of the combustion control; electrical ignition means; and an energizing circuit for said electrical ignition means, comprising a timed electrical element affecting the second-mentioned timed switch.

9. A controller for fluid fuel burners comprising, electric ignition means, an energizing circuit for said ignition means comprising a biased-open circuit breaker, an elec- 85 trically-timed element normally holding said circuit breaker closed, an electric circuit ineluding said timed element in parallel'with the ignition means and beyond the circuit breaker, a starting switch, and means con- 40 trolled by said starting switch to move the cirlguit breaker to closed .position against its ias. v In. witness whereof, I have hereunto set my hand at Minneapolis, Minnesota, this 6th day of March, A. D. one thousand nine hundred and twenty eight.

- DANIEL G. TAYLOR. 

